The present invention relates to technology which can flexibly expand, change or delete functions of tone generating apparatus.
Digital technology advance makes it possible to reduce the cost of realizing many of diversified functions developed in the prior art for electronic musical instruments.
To provide electronic musical instruments with such functions, the cost of operation members for selecting or setting instrument functions is often more expensive than the cost of realizing the functions per se. As a result, some electronic musical instruments employ a reduced number of operation members by assigning functions to simultaneous operation of a plurality of operation members. This, however, sacrifices the instrument operability.
A critical work in designing products is to determine specifications of products, or determine functions of products (here, electronic musical instruments). If change (addition, deletion) of product specifications happens to be required after the product design work started, an additional work of changing the design is inevitable. It is desired to minimize the additional work for change of product specifications since the working hours assigned to designing products are limited.
In the prior art electronic musical instruments, a control program which is run by CPU to control the entire system is written so as to describe and arrange control contents executed by CPU in response to event occurrences, such as operations of operation members.
As a result, even slightest change of the product design, such as changing applications of operation members requires a great amount of work to change the control program.